Does Dan's neighborhood hood-popper need to have his head examined?

Dear Car Talk

Dear Car Talk | Aug 01, 2007

Dear Tom and Ray:

I just wanted to know if there is any long-term benefit to regularly opening the front hood of your car right after you park it. Is this a quick method to cool off the engine that will prolong its life somehow? You see, I have a neighbor who insists on keeping his hood open whenever he gets home. I call him "The Great Hoodini." He used to drive an early-'90s T-bird, and just recently purchased a new Korean import. I wondered if he'd use the same miracle hood technique with his new car, and sure enough, hood's up! Sometimes he forgets about the open hood and leaves the car in his driveway for hours that way. It always appears like he's working on his vehicles. This hood obsession intrigues me to no end. Is it normal, or does this guy need to get his "hood" examined? Please advise. -- Daniel

RAY: Excessive heat is not a friend to your engine. So, sure, opening the hood to help the engine dissipate heat is a fine thing to do. If you have the time.

TOM: It's also a good way to get your battery stolen!

RAY: Heat harms the engine because it causes fluids to break down more quickly, and it does a number on belts, hoses, bushings and motor mounts.

TOM: However, most cars are fully equipped to dissipate the heat they generate. They have cooling systems that do the job while the car is running. And after the engine is shut off, when heat can temporarily build up, cars have fans that will continue to run, even after you've walked away from the car and are already sitting down to your first bite of a kielbasa sub. So it's not something the average person needs to worry about.

RAY: But if you're an AOC (automotive obsessive-compulsive), like your neighbor is, Daniel, then, yes, opening the hood when you park -- or even just releasing the hood latch and letting the hood pop open an inch or two -- will allow the engine to cool faster. It certainly can't hurt. And if you live in a hot, desert climate, it might even provide some real benefits in the summer months, when the ambient temperature is 110 degrees.

TOM: Of course, if you do pop the hood latch after driving, you have to be sure to remember to close the hood securely before you drive away again. While leaving the hood ajar to dissipate heat is good for the engine, having the hood fly up while you're doing 65 mph is bad for the engine ... since the engine is usually the first thing to hit the guardrail.

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